The present invention relates to datacommunication networks in which messages are sent between origination nodes and destination nodes. The invention also relates to methods of providing a high availability in datacommunications networks, particularly in networks wherein nodes are added and/or removed in an unpredictable way.
In various known datacommunication networks the status of different nodes is monitored in different ways so as to obtain some knowledge about the availability of the particular nodes. For example different algorithms can be used to obtain information about the availability of the nodes. In most cases, however, the networks themselves have to be of a particular kind, or the nodes have to be of some particular kind, or both, in order to be able to obtain such information. Particularly no satisfactory solution has been found to control the availability of nodes in a network, the configuration of which is not known or which changes in an unpredictable manner.
Today it is common knowledge to distribute software and t he flexibility of ordinary personal computers as far as the receivability and delivery of applications is concerned has increased considerably. Computers are also connected in more in varying manners and a network is resulting in which there is an extremely high number of different routes to the same destination, which network however also changes, or evolves, dynamically. German Patent DE-C4304916 shows a network including datacommunication stations and which is dynamically reconfigurable which means that stations can be added during the operation of the network. Between an origination station for a data message and a final receiving station, a number of stations may exist which can contain algorithms for routing the message. These algorithms can also handle the situation of sending the message another way when a particular communication link has been interrupted. When a new station is added, said station will itself search for a central communication station. According to this document a central communication station is presupposed for keeping control and it is not enabled to provide information about the availability level for particular stations and to obtain a sufficient or desired degree of availability.
German Patent DE-C4428349 relates to routing in a communication network and of achieving a sufficient availability level through allocation of a sufficient amount of alternative routes. In the document is described an algorithm for selecting the route which is the best to use. Said route is excluded from being selected as long as there are other routes if it has indicated that it is busy a predetermined number of times. However, the document does not at all discuss how different routes are established and it does not relate to the situation when new stations are added. In continuously evolving communication networks it is becoming more and more important to be able to obtain information about which is the actual availability, i.e. which is the probability of success when a message is sent from one node to another, but for example also to be able to obtain some information about the time it might take to send a message from one point to another and with what probability of success in what time etc.
If for example messages are sent from a client or a customer administration system (CAS), i.e. any origination node, it is actually possible to say something about the availability of said node. For a destination node such as for example a service management application system (SMAS) or any other application system handling incoming messages, it is also possible to influence the availability or the access. For example it is possible to require a high availability connection to the network such as for example Internet or an intranet. This is however not the only thing that affects the availability that is experienced by an origination system or a user since between an origination node and a destination node, there are large number of intermediate nodes such as for example proxies, which may go down quite often, with serving means, such as for example WEB-servers, mail servers, proxy servers and software crashes occur more or less frequently. Whereas it is normally possible to more or less accurately predict the accessibility or availability of an origination node and a destination node themselves as well as the connection to the global communication network itself, it is extremely difficult to say something about the availability an origination node, or rather the actual user, experiences of a destination node because of all the intermediate equipment or the intermediate nodes, particularly if the network structure changes dynamically through addition (and/or removal) of equipment or nodes.
In a network in which a centralized node is provided keeping information about all the other nodes, messages etc., such as for example an X0.25 network, it is generally less problematic. However, the use of such a solution, i.e. a centralized node, is inflexible or it requires too much intelligence from the application.
What is needed is therefore a datacommunications network with a number of origination nodes, a number of destination nodes and a number of intermediate nodes in which messages are sent from origination nodes via a number of intermediate nodes to a destination node and in which network nodes can be added and/or removed in an unpredictable way and for which the availability can be affected or controlled in order to establish a high availability connection over an independently evolving network or at least a connection with a sufficient availability.
A communications network is also needed in which it is possible to add new equipment in an unpredictable and independent way and still being able to establish the best choice of route. Particularly a network is needed through which the receiving side can be made as available as possible to a sending side. Still further it is desirable to provide for a high availability even if the number of nodes is very high. Particularly a structure is needed through which the actual need of availability can be satisfied to the highest possible extent and then be extended gradually so that either more messages can be sent or so that the availability can be increased. Particularly there is a need to be able to provide for high availability communication based on ordinary computers in a network with an unknown configuration which is cost-effective, easy to introduce and which can be widely used. A network is also needed wherein there are no particular requirements as to the structure of the network or the nodes themselves and which can be implemented using common computers and common communication methods.
A method of providing high availability communication in a data communication network is also needed as well as a method of providing high availability communication in an independently evolving network particularly offering a high availability communication to the origination node as to destination nodes for their incoming communication.
Therefore a datacommunications network is provided wherein at least a destination node has access to a basic functionality from which a functionality application is offered to other nodes which can fetch it from said destination node. When said functionality application including specific software is fetched by a destination node, a routing functionality application is accompanying or associated with said functionality application.
A functionality application which is considered to be attractive for many users is selected for being associated with the routing functionality and when it has been installed in the node, it is made available to other nodes in a higher hierarchical layer so that the chance that it is fetched by an overlying node is high. In alternative embodiments there are more than one functionality application, e.g. two or more applications are offered. Advantageously a number of parallel nodes in each of at least two different layers fetch the functionality application from a respective node(s) in a lower layer so that said nodes also get access to the routing functionality for routing messages from originating nodes or from nodes in a higher layer. In an advantageous embodiment the functionality application is an availability information application. Thus, a node receiving a stream of messages or of information, i.e. a destination node, can offer a service with processing intelligence and high availability support through offering particular applications such as an availability information application which other nodes or computers easily can fetch via the network, for example Internet or an intranet. The other nodes, computers or proxies, can then start up an application with an availability information functionality and then in turn also offer a routing application as a service to other nodes. A sending or an originating node in this manner is provided with a number of different alternative routes with processing intelligence, e.g. the availability information application and furthermore also a functionality supporting routing of the communication so as to provide for a high availability for said origination node or intermediate nodes acting as origination nodes.
It should be noted that a high availability and routing possibility is only provided up to and including the nodes having accessed the routing functionality but of course even if this functionality has not been fetched to the higher layers, routing is still improved also if it only covers the two lowermost layers (or more) but it should be clear that the more nodes that get access to the availability information and the routing functionality, the more advantage can be taken thereof. Advantageously each installation of the availability information application (or some other application specific application) and the xe2x80x9caccompanyingxe2x80x9d routing application is provided with a unique identification. Then information about the availability for different routes through the network can easily be collected so as to establish whether, and through which route, the desired availability can be achieved.
The simplest form of a routing application is a simple switch-over when a response message either from a malfunctioning route or from other routes indicates that the route that is being used does not function. The applications (availability information application and routing application) which are offered to enable high availability communication to the origination node, can also serve two purposes in that they also give the nodes fetching them the possibility to, in their turn, offer a higher availability for their incoming communication.
The applications are advantageously offered in a multistage procedure through which several nodes or computers consecutively fetches and implements the applications.
In a particular embodiment the routing functionality software is provided to nodes in at least two different layers above the destination nodes, routing being controllable also for messages/information sent from a destination node towards origination nodes. In a particular embodiment at least two duplicated data streams are provided between nodes in at least two different layers, the routing functionality being used for selecting the route which to the highest extent fulfills the given needs. The routing functionality particularly includes routing algorithms which are used to find the best routing alternative so as to provide a desired/sufficient degree of availability. Particularly routing is performed, i.e. a route is selected, at the receiving side, e.g. a destination node. The datacommunication network comprises a global datacommunication network, e.g. an intranet or Internet. As referred to above, in a most advantageous embodiment high availability routing is provided for communication of messages both towards a destination node and towards an origination node. In a particular embodiment at least one origination node comprises a customer administration system (CAS) or a client and at least one destination node, in a particular embodiment comprises a service management system (SMS). In at least a number of nodes serving means are provided such as for example WEB-servers, mail servers (or proxy servers as referred to below). In a particular embodiment a client is a WEB-client addressing via Internet or an intranet. At least a number of intermediate nodes, in a particular embodiment, comprise proxies with proxy servers. In a specific embodiment availability information for a specific receiver is stored in storing means such as for example small data storing means, e.g. a cookie (c.f. Internet) communicating with the origination node or more generally a node overlying another, or several other, nodes. Information is continuously updated by the availability functionality. Thus there is no centralized storing of data (e.g. routing DB) for the whole network, however there is at least one routing DB per destination node.
In a particularly advantageous embodiment the routing functionality is provided by a JAVA(trademark) program comprising an interface towards a WEB-server, a calculation part for selecting to which node to route a message and a sender for sending the message to the selected node. Of course other alternatives are also possible and other functionality applications can be offered, or even different functionality applications in some cases, the main thing being that they appear attractive to the users so that as many users as possible fetch the functionality, thereby increasing the overall availability of the network. It should be clear that the concepts origination and destination nodes are not fixed since an intermediate node can act both as an origination node and a destination node.